The use of hydrochlorides of functionalized aminosilanes, such as 3-(N-vinylbenzyl-2-aminoethyl)aminopropyltrimethoxysilane or 3-(N-benzyl-2-aminoethyl)aminopropyltrimethoxysilane, as adhesion promoters is well known. U.S. Pat. No. 4,902,556, European Patent 353,766 and U.S. Pat. No. 4,849,294 disclose the use of adhesion promoters for coating of metals, preferably copper and iron, with polyolefins or epoxide resins. Adhesion promotion on glass surfaces is disclosed in European Patent 338,128, International Application WO 8,800,527, U.S. Pat. No. 4,499,152, U.S. Pat. No. 4,382,991, U.S. Pat. No. 4,330,444 and German Patent 2,802,242 (adhesion promoters for diverse resin systems on glass fibers), and Belgian Patent 845,040 (adhesion promoters for epoxide resins on plate glass for improved alkali resistance). Their use as adhesion promoters for oxidic fillers in diverse organic polymers is also disclosed (Japanese Patent 01/259,369 and European Patent 176,062). For ecological reasons, such as reduction of the chemical oxygen demand in effluents and operating safety reasons, the use of adhesion promoters in aqueous systems is of advantage. However, the above referred to substances are only sparsely soluble in water. Aqueous formulations thereof are not possible without the use of stabilizing additives or significant amounts of organic acids, and even then their use only in low concentrations of less than 1% is possible (see Japanese Patent 62/243,624, U.S. Pat. No. 4,499,152, U.S. Pat. No. 4,382,991, U.S. Pat. No. 4,330,444 and German Patent 2,802,242).